Yes, TARZANS is a Scrabble word!

Letter values in Scrabble US: T 1, A 1, R 1, Z 10, A 1, N 1, S 1.

Is it a valid word?

TARZANS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

(sometimes used ironically) a man of great strength and agility (after the hero of a series of novels by Edgar Rice Burroughs)
a man raised by apes who was the hero of a series of novels by Edgar Rice Burroughs

Also: tarzan of the apes.